Navigation devices are known and used in different specific embodiments. They essentially include a position determining device, which its position on the earth's surface in an essentially known way with the aid of signals transmitted by GPS satellites or, in the future, by Galileo satellites. Furthermore, a routing device is known, which, on the basis of this position, calculates a route to a destination predefined by the user of the navigation device and outputs appropriate directions visually and/or acoustically. For this purpose, information regarding the route and road network of the area to be traveled is used for routing for a motor vehicle, such information being stored on a replaceable CD-ROM or DVD, for example. Due to the large amount of data needed in this case, it is known that, for example, only the countries of Central Europe with their route information are stored on a CD-ROM, and another CD-ROM must be inserted for other countries.
In addition, today's navigation devices receive information, for example, about a temporary traffic jam or a road closure on the previously calculated travel route with the aid of so-called TMC (traffic message control) data. These TMC data are transmitted by radio stations and received by the navigation device or navigation system using a tuner appropriate for this purpose. TMC data are transmitted simultaneously with the actual radio signals, i.e., for example, a piece of music. The information about the radio transmitters or the frequencies at which these TMC data are transmitted is also stored on the CD-ROM provided for this country or area. Navigation devices are also known which are able to receive TMC data with the aid of a so-called dual-tuner concept, i.e., using two receivers for radio signals.
It is considered disadvantageous here that the navigation device having the associated tuners or radio receivers constantly attempts to receive the appropriate TMC data or to look for a TMC transmitter for all countries that are stored on the CD-ROM or DVD. The compilation time is therefore unnecessarily extended, and the response time until all relevant TMC messages are compiled for the area traveled at a given time is too long. In addition, the tuners are overburdened with unnecessary tasks, so that even in the essentially known dual-tuner concept, the problem arises that a correct transmitter search, for example, for RDS functionalities, is no longer possible to perform.